The invention relates to an installation for separating and purifying solids from a suspension and/or for leaching out solid particles, containing:
a cylinder having a piston which is movable therein and which with a sealing part bears against an interior wall of the cylinder to provide a seal,
a filter which is connected to the piston and which delimits a washing column chamber located above the filter in the cylinder.
a feed line for feeding the suspension of the solid particles to the cylinder and
a discharge line for discharging the liquid from the washing column chamber after filtering through the filter.
An installation, or washing column, of this type is disclosed in Netherlands Patent Application no. 7 106 457 in the name of the Applicant. In said known installation, when the piston is in the lowermost position, the suspension of solid particles in a liquid is passed through the piston into the washing column chamber. A packed bed of particles, for example ice crystals, is located in the upper part of the washing column chamber. The piston is then displaced upwards until it comes into contact with the packed bed. During this operation the liquid is forced through the filter to a discharge line. The particles remain behind on the filter and add to the packed bed from the bottom. The packed bed is melted or scraped off at the top and the purified particles (ice crystals) are discharged from the washing column chamber.
A discontinuous piston washing column of this type has the disadvantage that the purification process is difficult to carry out on a large scale. Furthermore, the system of movable feed and discharge lines requires additional pneumatics and complex seals. Furthermore, it is difficult to scale up the known piston washing column.